#include <libavformat/avformat.h>
#include <libavcodec/avcodec.h>
#include <libswscale/swscale.h>
#include <stdio.h>
#include <SDL/SDL.h>
#include <SDL/SDL_thread.h>
#define SDL_AUDIO_BUFFER_SIZE 1024
typedef struct PacketQueue {
	AVPacketList *first_pkt, *last_pkt;
	int nb_packets;
	int size;
	SDL_mutex *mutex;
	SDL_cond *cond;
} PacketQueue;
void packet_queue_init(PacketQueue *q) {
	memset(q, 0, sizeof(PacketQueue));
	q->mutex = SDL_CreateMutex();
	q->cond = SDL_CreateCond();
}
int packet_queue_put(PacketQueue *q, AVPacket *pkt) {
	AVPacketList *pkt1;
	if (av_dup_packet(pkt) < 0) {
		return -1;
	}
	pkt1 = av_malloc(sizeof(AVPacketList));
	if (!pkt1)
		return -1;
	pkt1->pkt = *pkt;
	pkt1->next = NULL;
	SDL_LockMutex(q->mutex);
	if (!q->last_pkt)
		q->first_pkt = pkt1;
	else
		q->last_pkt->next = pkt1;
	q->last_pkt = pkt1;
	q->nb_packets++;
	q->size += pkt1->pkt.size;
	SDL_CondSignal(q->cond);
	SDL_UnlockMutex(q->mutex);
	return 0;
}
int quit = 0;
static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block) {
	AVPacketList *pkt1;
	int ret;
	SDL_LockMutex(q->mutex);
	for (;;) {
		if (quit) {
			ret = -1;
			break;
		}
		pkt1 = q->first_pkt;
		if (pkt1) {
			q->first_pkt = pkt1->next;
			if (!q->first_pkt)
				q->last_pkt = NULL;
			q->nb_packets--;
			q->size -= pkt1->pkt.size;
			*pkt = pkt1->pkt;
			av_free(pkt1);
			ret = 1;
			break;
		} else if (!block) {
			ret = 0;
			break;
		} else {
			SDL_CondWait(q->cond, q->mutex);
		}
	}
	SDL_UnlockMutex(q->mutex);
	return ret;
}
int decode_interrupt_cb(void) {
	return quit;
}
void audio_callback(void *userdata, Uint8 *stream, int len) {
	AVCodecContext *aCodecCtx = (AVCodecContext *) userdata;
	int len1, audio_size;
	static uint8_t audio_buf[(AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2];
	static unsigned int audio_buf_size = 0;
	static unsigned int audio_buf_index = 0;
	while (len > 0) {
		if (audio_buf_index >= audio_buf_size) {
			audio_size = audio_decode_frame(aCodecCtx, audio_buf,
					sizeof(audio_buf));
			if (audio_size < 0) {
				audio_buf_size = 1024;
				memset(audio_buf, 0, audio_buf_size);
			} else {
				audio_buf_size = audio_size;
			}
			audio_buf_index = 0;
		}
		len1 = audio_buf_size - audio_buf_index;
		if (len1 > len)
			len1 = len;
		memcpy(stream, (uint8_t *) audio_buf + audio_buf_index, len1);
		len -= len1;
		stream += len1;
		audio_buf_index += len1;
	}
}
PacketQueue audioq;
int main(int argc, char *argv[]) {
	url_set_interrupt_cb(decode_interrupt_cb);
	AVFormatContext *pFormatCtx;
	int i, videoStream, audioStream;
	AVCodecContext *vCodecCtx;
	AVCodecContext *aCodecCtx;
	AVCodec *vCodec;
	AVCodec *aCodec;
	AVFrame *pFrame;
	AVFrame *pFrameRGB;
	AVPacket packet;
	int frameFinished = 0;
	int numBytes;
	uint8_t *buffer;
	struct SwsContext *pSwsCtx;
	SDL_AudioSpec wanted_spec, spec;
	// Register all formats and codecs
	av_register_all();
	const char *filename = "/root/Desktop/test.flv";
	// Open video file
	if (av_open_input_file(&pFormatCtx, filename, NULL, 0, NULL) != 0)
		return -1; // Couldn't open file

	// Retrieve stream information
	if (av_find_stream_info(pFormatCtx) < 0)
		return -1; // Couldn't find stream information

	// Dump information about file onto standard error
	dump_format(pFormatCtx, 0, filename, 0);

	// Find the first video stream
	videoStream = -1;
	audioStream = -1;
	for (i = 0; i < pFormatCtx->nb_streams; i++) {
		if (pFormatCtx->streams[i]->codec->codec_type == CODEC_TYPE_VIDEO
				&& videoStream < 0) {
			videoStream = i;
		}
		if (pFormatCtx->streams[i]->codec->codec_type == CODEC_TYPE_AUDIO
				&& audioStream < 0) {
			audioStream = i;
		}
	}
	if (videoStream == -1)
		return -1; // Didn't find a video stream
	if (audioStream == -1)
		return -1;
	// Get a pointer to the codec context for the video stream
	vCodecCtx = pFormatCtx->streams[videoStream]->codec;
	// Find the decoder for the video stream
	vCodec = avcodec_find_decoder(vCodecCtx->codec_id);
	if (vCodec == NULL) {
		fprintf(stderr, "Unsupported codec!\n");
		return -1; // Codec not found
	}
	// Open codec
	if (avcodec_open(vCodecCtx, vCodec) < 0)
		return -1; // Could not open codec
	aCodecCtx = pFormatCtx->streams[audioStream]->codec;
	wanted_spec.freq = aCodecCtx->sample_rate;
	wanted_spec.format = AUDIO_S16SYS;
	wanted_spec.channels = aCodecCtx->channels;
	wanted_spec.silence = 0;
	wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE;
	wanted_spec.callback = audio_callback;
	wanted_spec.userdata = aCodecCtx;
	if (SDL_OpenAudio(&wanted_spec, &spec) < 0) {
		fprintf(stderr, "SDL_OpenAudio: %s/n", SDL_GetError());
		return -1;
	}
	aCodec = avcodec_find_decoder(aCodecCtx->codec_id);
	if (!aCodec) {
		fprintf(stderr, "Unsupported codec!/n");
		return -1;
	}
	avcodec_open(aCodecCtx, aCodec);
	packet_queue_init(&audioq);
	SDL_PauseAudio(0);
	// Allocate video frame
	pFrame = avcodec_alloc_frame();
	// Allocate an AVFrame structure
	pFrameRGB = avcodec_alloc_frame();
	if (pFrameRGB == NULL)
		return -1;
	// Determine required buffer size and allocate buffer
	numBytes = avpicture_get_size(PIX_FMT_RGB24, vCodecCtx->width,
			vCodecCtx->height);
	buffer = (uint8_t *) av_malloc(numBytes * sizeof(uint8_t));

	// Assign appropriate parts of buffer to image planes in pFrameRGB
	// Note that pFrameRGB is an AVFrame, but AVFrame is a superset
	// of AVPicture
	avpicture_fill((AVPicture *) pFrameRGB, buffer, PIX_FMT_RGB24,
			vCodecCtx->width, vCodecCtx->height);

	// Read frames and save first five frames to disk
	while (av_read_frame(pFormatCtx, &packet) >= 0) {
		// Is this a packet from the video stream?
		if (packet.stream_index == videoStream) {
			// Allocate video frame
			pFrame = avcodec_alloc_frame();
			int w = vCodecCtx->width;
			int h = vCodecCtx->height;
			// Decode video frame
			avcodec_decode_video2(vCodecCtx, pFrame, &frameFinished, &packet);
			pSwsCtx = sws_getContext(w, h, vCodecCtx->pix_fmt, w, h,
					PIX_FMT_RGB565, SWS_POINT, NULL, NULL, NULL);
			if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) {
				fprintf(stderr, "Could not initialize SDL - %s/n",
						SDL_GetError());
				exit(1);
			}
			SDL_Surface *screen;
			screen = SDL_SetVideoMode(vCodecCtx->width, vCodecCtx->height, 0,
					0);
			if (!screen) {
				fprintf(stderr, "SDL: could not set video mode - exiting/n");
				exit(1);
			}
			SDL_Overlay *bmp;
			bmp = SDL_CreateYUVOverlay(vCodecCtx->width, vCodecCtx->height,
					SDL_YV12_OVERLAY, screen);
			SDL_Rect rect;
			if (frameFinished) {
				SDL_LockYUVOverlay(bmp);
				AVPicture pict;
				pict.data[0] = bmp->pixels[0];
				pict.data[1] = bmp->pixels[2];
				pict.data[2] = bmp->pixels[1];
				pict.linesize[0] = bmp->pitches[0];
				pict.linesize[1] = bmp->pitches[2];
				pict.linesize[2] = bmp->pitches[1];
				// Convert the image into YUV format that SDL uses
				img_convert(&pict, PIX_FMT_YUV420P, (AVPicture *) pFrame,
						vCodecCtx->pix_fmt, vCodecCtx->width,
						vCodecCtx->height);
				SDL_UnlockYUVOverlay(bmp);
				rect.x = 0;
				rect.y = 0;
				rect.w = vCodecCtx->width;
				rect.h = vCodecCtx->height;
				SDL_DisplayYUVOverlay(bmp, &rect);
			}
		} else if (packet.stream_index == audioStream) {
			packet_queue_put(&audioq, &packet);
		} else {
			av_free_packet(&packet);
		}
		SDL_Event event;
		SDL_PollEvent(&event);
		switch (event.type) {
		case SDL_QUIT:
			SDL_Quit();
			exit(0);
			break;
		default:
			break;
		}
	}
	// Free the RGB image
	av_free(buffer);
	av_free(pFrameRGB);

	// Free the YUV frame
	av_free(pFrame);

	// Close the codec
	avcodec_close(vCodecCtx);

	// Close the video file
	av_close_input_file(pFormatCtx);

	return 0;
}
int img_convert(AVPicture *dst, enum PixelFormat dst_pix_fmt,
		const AVPicture *src, enum PixelFormat src_pix_fmt, int src_width,
		int src_height) {
	int w;
	int h;
	struct SwsContext *pSwsCtx;
	w = src_width;
	h = src_height;
	pSwsCtx = sws_getContext(w, h, src_pix_fmt, w, h, dst_pix_fmt, SWS_BICUBIC,
			NULL, NULL, NULL);
	sws_scale(pSwsCtx, src->data, src->linesize, 0, h, dst->data,
			dst->linesize);
	//这样释放掉pSwsCtx的内存
	return 0;
}

int audio_decode_frame(AVCodecContext *aCodecCtx, uint8_t *audio_buf,int buf_size) {
	static AVPacket pkt;
	static uint8_t *audio_pkt_data = NULL;
	static int audio_pkt_size = 0;
	int len1, data_size;
	for (;;) {
		while (audio_pkt_size > 0) {
			data_size = buf_size;
			len1 = avcodec_decode_audio2(aCodecCtx, (int16_t *) audio_buf,
					&data_size,
					audio_pkt_data, audio_pkt_size);
			if (len1 < 0) {
				audio_pkt_size = 0;
				break;
			}
			audio_pkt_data += len1;
			audio_pkt_size -= len1;
			if (data_size <= 0) {
				continue;
			}
			return data_size;
		}
		if (pkt.data)
			av_free_packet(&pkt);
		if (quit) {
			return -1;
		}
		if (packet_queue_get(&audioq, &pkt, 1) < 0) {
			return -1;
		}
		audio_pkt_data = pkt.data;
		audio_pkt_size = pkt.size;
	}

}

